Catalytic systems and technologies for carbonylation of an acetylenic or olefinic unsaturated compound have been proposed. Typical carbonylation reactions include a method which comprises allowing an acetylenic or olefinic unsaturated compound to react with carbon monoxide and a nucleophilic compound. In this method, a carbonylation catalyst comprises a Group VIII metal source of Periodic Table of the Elements and a phosphine which is a typical ligand.
EP-A1-106379, EP-A1-235864, EP-A1-274795 and EP-A1-279447 disclose catalytic systems for carbonylation comprising a palladium compound, a triarylphosphine and a proton acid and methods for carbonylation of an acetylenic unsaturated compound and an olefinic compound with the use of such catalytic systems.
Japanese Patent Publication No. 29212/1993 (JP-B-5-29212), Japanese Patent Application Laid-open No. 176549/1986 (JP-A-61-176549), Japanese Patent Application Laid-open No. 72649/1987 (JP-A-62-72649) and Japanese Patent Application Laid-open No. 154646/1988 (JP-A-63-154646) disclose carbonylation catalytic systems comprising a bivalent palladium compound, an organic phosphine and a proton acid, and methods for carbonylation of an acetylenic unsaturated compound and an olefinic compound by using the catalytic systems. The Japanese Patent Application Laid-open No. 154646/1988 (JP-A-63-154646) describes that a homogeneous compound is rather preferred as the palladium compound than a heterogeneous compound and that a phosphine having a heterocyclic group is used as the organic phosphine and, as an inert solvent, N-methylpyrrolidone is preferred.
Further, Japanese Patent Application Laid-open No. 215851/1992 (JP-A-4-215851) discloses a catalytic system for carbonylation which comprises a Group VIII metal source of Periodic Table of the Elements, a phosphine substituted with an aromatic substitute containing an imino-nitrogen atom, a proton source and an anion source of an alkylsulfonic acid, and a method for carbonylation of an acetylenic unsaturated compound and an olefinic compound using the catalytic system. Moreover, Japanese Patent Application Laid-open No. 21852/1992 (JP-A-4-21852) discloses a catalytic system comprising a Group VIII metal source, a phosphine having an imino-nitrogen atom-containing aromatic substituent, a proton source and an anion source of an alkylsulfonic acid, and a method of carbonylation of an acetylenic or olefinic unsaturated compound with the use of the catalytic system. There is described in these literatures, JP-A-4-215851 and JP-A-4-215852, that as the Group VIII metal source of Periodic Table of the Elements, a compound containing the Group VIII metal, specifically a palladium compound is rather preferred than an element in a metallic state.
According to these technologies, a methacrylic acid ester, for example, can be obtained from methylacetylene, carbon monoxide and an alcohol without using sulfuric acid in a large quantity. Therefore, these technologies are superior to the acetone-cyanohydrin method for a production of a methacrylic acid ester in a point that a methacrylic acid ester can be produced without exhausting industrial wastes such as waste sulfuric acid.
The catalytic systems used in the methods have, however, a significant disadvantage that they have a short catalyst life although having an initial activity to a certain extent, and thus they are not suitable as a catalyst for commercial use. By way of illustration, in carbonylation of an acetylenic unsaturated compound, use of a heterogeneous catalytic system comprising a catalytic component in a metallic state such as palladium black as the catalytic system results in not so much high catalytic activity and causes a significant decrease of the catalytic activity in a short period. When a homogeneous catalytic system containing a palladium compound such as palladium chloride is used as the catalytic system, the palladium compound is reduced in the course of the reaction to precipitate as a metallic simple substance in the reaction system, and a ligand such as an organic phosphine is oxidized which results in a decreased catalytic activity.
In fact, a practical use of a palladium compound as a component of the above-mentioned catalytic system in a carbonylation reaction results in metalation of palladium to rapidly precipitate or dispose in the reaction mixture and thus in decrease of the catalytic activity and reaction rate for carbonylation.
Further, as set forth in the Japanese Patent Application Laid-open No. 215852/1992 (JP-A-4-215852), when a catalytic system comprising a Group VIII element and an triarylphosphine as base components is incorporated with a tertiary amine, the catalytic properties of the catalyst is quite decreased in a carbonylation of an olefin. Therefore, in the method using a tertiary amine such as pyridine as described in the Japanese Patent Application Laid-open No. 215852/1992 (JP-A-4-215852), a phosphine having an aromatic substituent containing an imino-nitrogen atom (e.g., bisphenyl-2-pyridylphosphine) is required to be used as the phosphine, and components for the catalytic system are remarkably restricted. Moreover, the catalytic system comprising a palladium compound as the catalytic component shows insufficient catalytic activity.